Field and laboratory observations of the feeding ecology (natural diet, prey capture success, and prey handling) of Oecobius maculatus Simon 1870 were combined in this study to reveal the level of trophic specialization by this species. Natural prey were investigated on the Croatian island of Brac. Field observations revealed that although spiders captured prey belonging to five invertebrate orders, the most frequently captured prey were ants, which were also the most abundant available prey in the locality. In laboratory experiments, O. maculatus spiders accepted three other prey types with a higher probability than ants and were significantly more efficient at capturing and handling flies than ants. These results suggest that this species is a stenophagous generalist with a narrow prey range due to ecological circumstances.